Artificial intelligence is the science and engineering of making intelligent machines, especially computer programs. Applications of artificial intelligence include game playing and speech recognition.
Chinese antithetical couplets called “dui4-lian2” (in Pinyin) are considered an important Chinese cultural heritage. The teaching of antithetical couplets was an important method of teaching traditional Chinese for thousands of years. Typically, an antithetical couplet includes two phrases or sentences written as calligraphy on vertical red banners, typically placed on either side of a door or in a large hall. Such couplets are illustratively displayed during special occasions such as weddings or during the Spring Festival, i.e. Chinese New Year. Other types of couplets include birthday couplets, elegiac couplets, decoration couplets, professional or other human association couplets, and the like.
Chinese antithetical couplets use condensed language, but have deep and sometimes ambivalent or double meaning. The two sentences making up the couplet are illustratively called the “first scroll sentence” and the “second scroll sentence.”
An example of a Chinese couplet is  and  where the first scroll sentence is  and the second scroll sentence is  The correspondence between individual words of the first and second sentences is shown as follows:
  (sea)  (sky)  (wide)  (high)  (allows)  (enable)  (fish)  (bird)  (jump)  (fly)
Antithetical couplets can be of different length. A short couplet can include one or two characters while a longer couplet can reach several hundred characters. The antithetical couplets can also have diverse forms or relative meanings. For instance, one form can include first and second scroll sentences having the same meaning. Another form can include scroll sentences having the opposite meaning. However, no matter which form, Chinese couplets generally conform to rules or principles such as the following:
Principle 1: The two sentences of the couplet generally have the same number of words and total number of Chinese characters. Each Chinese character has one syllable when spoken. A Chinese word can have one, two or more characters, and consequently, be pronounced with one, two or more syllables. Each word of a first scroll sentence should have the same number of Chinese characters as the corresponding word in the second scroll sentence.
Principle 2: Tones (e.g. “Ping” and “Ze”  in Chinese) are generally coinciding and harmonious. The traditional custom is that the character at the end of first scroll sentence should be  (called tone “Ze” in Chinese). This tone is pronounced in a sharp downward tone. The character at the end of the second scroll sentence should be  (called tone “Ping” in Chinese). This tone is pronounced with a level tone.
Principle 3: The parts of speech of words in the second sentence should be identical to the corresponding words in the first scroll sentence. In other words, a noun in the first scroll sentence should correspond to a noun in the second scroll sentence. The same would be true for a verb, adjective, number-classifier, adverb, and so on. Moreover, the corresponding words must be in the same position in the first scroll sentence and the second scroll sentence.
Principle 4: The contents of the second scroll sentence should be mutually inter-related with the first scroll sentence and the contents cannot be duplicated in the first and second scroll sentences.
In some cases, couplets are accompanied by a banner (a.k.a., a streamer), typically horizontally placed above a door between the vertical couplet banners. A banner, most commonly a phrase composed of 4 Chinese characters, is used to attach with a couplet to summarize, emphasize and complement the meaning of the couplet. Although the length of a banner can vary from 2 characters to 5 or 6 characters, a banner most typically has 4 characters. A basic requirement for a banner is that its meaning should fit the meaning of the first and second scroll sentences. For example, the banner for the couplet   is  Literally translated as “winter goes by, the mountain is bright and the river is beautiful; spring comes, then bird is singing and the flowers smell good”.
However, no matter which form, a banner for a Chinese couplet generally conforms to rules or principles such as the following:
Principle 1: The banner generally consists of 4 Chinese characters. In a minority of cases, a banner consists of 2, or 3, or 5 or more characters. Each Chinese character generally has one syllable when spoken.
Principle 2: Tones are generally coinciding and harmonious. But normally, there is no strict requirement in terms of the correspondence between banner and either first scroll of sentence or second scroll of sentence.
Principle 3: The content of the banner should be mutually inter-related with the first and second scroll sentences, and the content generally cannot be duplicated in the first and second scroll sentences.
Chinese-speaking people often engage in creating new couplets and banner as a form of entertainment. One form of recreation is one person makes up a first scroll sentence and challenges others to create, on the spot, an appropriate second scroll sentence. A further challenge is sometimes made to create the banner after the first and second scroll sentence are given. Thus, creating banners, like creating second scroll sentences, challenges participants' linguistic, creative, and other intellectual capabilities.
In general, an automatic generation of second scroll sentences (e.g., given a first scroll sentence) and/or banners (e.g., given first and second scroll sentences) would be an appropriate and well-regarded application of artificial intelligence.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.